I recently updated to Fedora 22; an older nvida card using the Nouveau driver.

This morning KDE started, but only displayed the startup/background. Restarting eventually got me to a somewhat-working plasma session in which the "starting" apps (e.g., Dolphin, an xterm) are started, but the task bar and screen controls simply don't work. I can interact with the open applications but not the desktop.

I'm able to start and use Gnome with no issues.

I cleared .cache and renamed .kde; a new .kde appeared. Same issues.

Bug handling managed to make one trace, but /var/log/messages has references to numerous segfaults:
Jun  5 06:03:35 linuxgame kernel: QXcbEventReader[3226]: segfault at 7f982df5d1e9 ip 00007f982df5d1e9 sp 00007f982df16da0 error 14 in locale-archive[7f982e232000+66ba000]
Jun  5 07:51:39 linuxgame kernel: kactivitymanage[4466]: segfault at 7f3e42e11cf0 ip 00007f3e43059661 sp 00007ffe9f068d88 error 4 in libQt5Sql.so.5.4.1[7f3e43045000+3f000]
Jun  5 07:51:39 linuxgame kernel: QXcbEventReader[4784]: segfault at 7f77510fb1e9 ip 00007f77510fb1e9 sp 00007f77510b4da0 error 14 in locale-archive[7f77513d0000+66ba000]
Jun  5 17:33:27 linuxgame kernel: QXcbEventReader[2967]: segfault at 7f073cd711e9 ip 00007f073cd711e9 sp 00007f073cd2ada0 error 14 in locale-archive[7f073d046000+66ba000]
Jun  5 17:51:16 linuxgame kernel: kactivitymanage[2410]: segfault at 7f0fecbafcf0 ip 00007f0fecdf7661 sp 00007ffe14e47868 error 4 in libQt5Sql.so.5.4.1[7f0fecde3000+3f000]
Jun  5 17:51:16 linuxgame kernel: kscreen_backend[9792]: segfault at 7fa7cc61e718 ip 00000038fe4dd922 sp 00007ffe8b3ac508 error 4 in libQt5Gui.so.5.4.1[38fe400000+517000]


Application: kwin_x11 (5.3.0)

Qt Version: 5.4.1
Operating System: Linux 4.0.4-303.fc22.x86_64 x86_64
Distribution (Platform): Fedora RPMs

-- Information about the crash:
<In detail, tell us what you were doing  when the application crashed.>

Logged in after choosing Plasma as windows manager.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fbd90cd6900 (LWP 2535))]

Thread 5 (Thread 0x7fbd81660700 (LWP 2550)):
#0  0x000000336a2f666d in poll () from /lib64/libc.so.6
#1  0x000000336ba49dbc in g_main_context_iterate.isra () from /lib64/libglib-2.0.so.0
#2  0x000000336ba4a142 in g_main_loop_run () from /lib64/libglib-2.0.so.0
#3  0x00007fbd82ec4696 in gdbus_shared_thread_func () from /lib64/libgio-2.0.so.0
#4  0x000000336ba710a5 in g_thread_proxy () from /lib64/libglib-2.0.so.0
#5  0x0000003369e07555 in start_thread () from /lib64/libpthread.so.0
#6  0x000000336a301f3d in clone () from /lib64/libc.so.6

Thread 4 (Thread 0x7fbd80e5f700 (LWP 2551)):
#0  0x000000336a2f666d in poll () from /lib64/libc.so.6
#1  0x000000336ba49dbc in g_main_context_iterate.isra () from /lib64/libglib-2.0.so.0
#2  0x000000336ba49ecc in g_main_context_iteration () from /lib64/libglib-2.0.so.0
#3  0x000000336ba49f09 in glib_worker_main () from /lib64/libglib-2.0.so.0
#4  0x000000336ba710a5 in g_thread_proxy () from /lib64/libglib-2.0.so.0
#5  0x0000003369e07555 in start_thread () from /lib64/libpthread.so.0
#6  0x000000336a301f3d in clone () from /lib64/libc.so.6

Thread 3 (Thread 0x7fbd797fe700 (LWP 2563)):
#0  0x000000336a2f83d3 in select () from /lib64/libc.so.6
#1  0x000000337f4d1dcf in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () from /lib64/libQt5Core.so.5
#2  0x000000337f4d38ce in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () from /lib64/libQt5Core.so.5
#3  0x000000337f4d3dfe in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#4  0x000000337f47ca8a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#5  0x000000337f29aff4 in QThread::exec() () from /lib64/libQt5Core.so.5
#6  0x00000039098c3935 in QQmlThreadPrivate::run() () from /lib64/libQt5Qml.so.5
#7  0x000000337f29fede in QThreadPrivate::start(void*) () from /lib64/libQt5Core.so.5
#8  0x0000003369e07555 in start_thread () from /lib64/libpthread.so.0
#9  0x000000336a301f3d in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7fbd5f6c3700 (LWP 2574)):
#0  0x0000003369e0c530 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00000033825806d4 in QTWTF::TCMalloc_PageHeap::scavengerThread() () from /lib64/libQt5Script.so.5
#2  0x0000003382580719 in QTWTF::TCMalloc_PageHeap::runScavengerThread(void*) () from /lib64/libQt5Script.so.5
#3  0x0000003369e07555 in start_thread () from /lib64/libpthread.so.0
#4  0x000000336a301f3d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7fbd90cd6900 (LWP 2535)):
[KCrash Handler]
#5  0x00000038ff017427 in QtPrivate::QFunctorSlotObject<void DBusFuture::continueWith<QString, KActivities::Manager::serviceOwnerChanged(QString const&, QString const&, QString const&)::{lambda(QString const&)#3}>(QFuture<QString> const&, KActivities::Manager::serviceOwnerChanged(QString const&, QString const&, QString const&)::{lambda(QString const&)#3}&&)::{lambda()#1}, 0, QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*) () from /lib64/libKF5Activities.so.5
#6  0x000000337f4b0b11 in QObject::event(QEvent*) () from /lib64/libQt5Core.so.5
#7  0x00000038ff9527cc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#8  0x00000038ff957e70 in QApplication::notify(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#9  0x000000337f47f24b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /lib64/libQt5Core.so.5
#10 0x000000337f481387 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /lib64/libQt5Core.so.5
#11 0x000000337f4d3cc2 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#12 0x00007fbd8a3e697d in QUnixEventDispatcherQPA::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt5/plugins/platforms/libqxcb.so
#13 0x000000337f47ca8a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#14 0x000000337f4845fc in QCoreApplication::exec() () from /lib64/libQt5Core.so.5
#15 0x0000003908605967 in kdemain () from /lib64/libkdeinit5_kwin_x11.so
#16 0x000000336a220790 in __libc_start_main () from /lib64/libc.so.6
#17 0x0000000000400bc9 in _start ()


Reproducible: Always

Steps to Reproduce:
1. Start Plasma session
2.
3.


Expected Results:  
Started valid plasma session with active controls.